Objective To detect the immune effect of FbaAmAb2 against the surface protein of group A Straptococcus (GAS),and explore the pathogenesis and therapy of GAS infections.Methods By subclonal and bacterial ELISA,the positive hybridoma cells were screened that can produce better titers of FbaAmAb2 against GAS-surface FbaA protein,and were injected into the peritoneal cavities of BALB/c mice to produce ascites.The collected ascites were performed to dilute,as follows,original ascite,1:2,1:4,1:8,and 1:16 to test tube agglutination.Based on the results,we selected appropriate dilution to passively immunize mice,and then challenged the mice with GAS,evaluating FbaAmAb2 neutralizing ability with GAS in mice by the survival rate of the immunized mice.Whether FbaAmAb2 could inhibit the binding of factor H to GAS was confirmed by the invasive inhibition assay.Results The IgG titer of bacteria solution ELISA is 1:160 and the titer of tube agglutination is 1∶8.The protect rates of FbaAmAb2 on preventing mice with GAS infections are as follows:66.67％ in original ascite and 1:2 diluted groups,and 50％ in 1:4 diluted group.Mice in each experimental group were evoked significantly protective immune responses compared with the PBS control by SPSS analysis.FbaAmAb2 can competitively inhibit factor H binding to the surface proteins FbaA of GAS,which decreased the entry of GAS into the cytoplasm of human epithelial cells through the binding of factor H.Conclusion FbaAmAb2 is promising to be used in emergent prevention or the clinical therapy for GAS infection and it is promising starting points for pharmacologic targeting and further development of new therapeutic agents for GAS.

Objective To investigate the efficacy and prognostic risk factors of ALL-R-2003 protocol in the treatment of relapsed childhood relapsed acute lymphoblastic leukemia (ALL) in single center. Methods A retrospective study of clinical data of 51 children with relapsed ALL from January 2004 to December 2014 was performed by using SPSS version 19.0 statistical software for statistical analysis. Results The median age at initial diagnosis of 51 patients was 5.5 years (range, 0.8-13.4 years). The median time from initial diagnosis to relapse was 25 months (range, 3-68 months) and follow-up time was 39 months (range, 3-116 months). The relapse rate in the standard-risk, intermediate-risk and the high-risk groups were 27.5 % (14/51), 29.4 %(15/51) and 43.1 % (22/51), respectively. The probability of 3-year overall survival (pOS) after relapse was (18.8±5.9)%and the probability of event free survival (pEFS) was (16.2±5.8)%. The 3-year pOS in very early relapse, early relapse and late relapse were 0, (11.7 ±7.7) % and (51.7 ±14.8) %, respectively (P= 0.000). There was no statistical difference in survival rate of different immunophenotype groups and sites of relapse (P> 0.05). The 3-year pOS of group S1, S2, S3, S4 were (50.0±35.4) %, (39.9±1.3) %, (10.0±9.5) % and 0, respectively (P=0.000). The 3-year pOS of bcr-abl and MLL gene positive groups were (25.0±21.7) %and 0, respectively, with no statistically significance compared with the negtive group [(24.1±12.0)%] (P>0.05). The 3-year pOS rates of children with bone marrow transplantation and without transplantation were (40.0 ±15.5) %and (13.0 ±5.9) % respectively (P= 0.038). Conclusions The children who in high risk group at initial diagnose are easily to meet earlier relapse and poorer prognosis. The survival period after relapse of bcr-abl or MLL gene positive cases is very short. Bone marrow transplantation can improve survival rate. Risk group at initial diagnose, relapse time and transplantation are the main factors influencing prognosis, and the relapse time and transplantation are the independent prognostic factors for relapsed childhood ALL.